The present invention relates generally to a multipurpose electromechanical device which provides a pumping function such as might be required in circulating a coolant through a vehicle engine as well as an electrical energy generating function to obviate the need for, for example, a separately driven vehicle alternator.
In the past, vehicles have included a prime mover, such as an internal combustion engine, which is addition to supplying energy to drive the vehicle, also provides energy to a number of other devices through a maze of V-belts, pulleys and the like. Specifically, such an engine may drive an electrical generator such as an alternator, a water pump, a power steering pump, an air-conditioner pump or compressor, various anti-pollution devices, as well as other auxiliary devices.
The typical alternator is engine driven by a V-belt and a relatively small diameter pulley, for example of the order of two and one half inches in diameter. The alternator therefore typically revolves at a relatively high speed generating a relatively high frequency alternating current voltage. With such a relatively high frequency alternating current voltage, stator core losses are relatively high, and with such a small diameter pulley, belt slippage may be a substantial problem. Prior to the development of my copending parent application, Ser. No. 734,116, now U.S. Pat. No. 4,095,922, larger pulleys and lower frequencies have heretofore not been practical.
It is also known in the prior art, for example in U.S. Pat. No. 2,660,865, to provide a common shaft for a pump and an electrical generator, however, such prior art approaches have amounted to little more than placing the two devices end to end with a common drive shaft so that the overall axial length, weight and cost, has been substantially the sum of those traits for the respective individual devices.
My copending application Ser. No. 734,116 has combined a vehicle generator with another vehicle pump such as an air conditioner compressor, water pump, or the like, eliminating several components and reducing the size and weight, as well as the cost of the resultant assembly.
For example in FIG. 5 of my copending application, there is illustrated a water pump alternator assembly wherein the alternator shares with the water pump the bearings typically found in such pumps. The alternator stator is mounted to the face of the water pump with the water pump shaft extending through the stator to support on the side thereof opposite the water pump a permanent magnet rotor as well as a drive pulley and fan. In this arrangement, the alternator stator and rotor, drive pulley and fan are located progressively more remote from the water pump face. With the pulley disposed substantially outboard of the pump bearings, considerable twisting force is applied to the pump shaft by way of the drive pulley substantially shortening bearing life. Further with the component arrangement of FIG. 5 of my aforementioned copending application, the pulley is disposed between the vehicle engine fan and the alternator, thereby impeding the flow of air through the alternator for cooling that alternator.